1. Field of the Invention
Apparatuses and methods consistent with the present invention relate to generating a reduced image, and more particularly, to generating a reduced image of an original image.
2. Description of the Related Art
Recently, various types of digital multimedia services using high definition televisions (HDTVs), digital multimedia broadcasting (DMB), or Internet Protocol (IP) TV have become activated as a result of the rapid development of technologies relating to digital moving image processing. In particular, since HDTVs provide a large size screen with a high image quality, products, such as set-top boxes for HDTVs or personal video recorders (PVRs) for HDTVs, need to enable a user to easily search for scenes or programs which the user desires to view. This function is generally provided through a reduced image called as a thumbnail image.
Thumbnail images are typically extracted using a direct current (DC) image extraction method using a DC component indicating the average of blocks in a spatial frequency domain represented by a discrete cosine transform (DCT) coefficient.
The DC image extraction method may be used in a Moving Picture Experts Group-4 (MPEG-4) based system using a technology for individually compressing and encoding each block in the spatial frequency domain represented by the DCT coefficient.
However, a current block is dependent on a previous block and encoded in an H.264 encoding block by intra prediction, and thus it is impossible to apply the above DC image extraction method.
Accordingly, in order to generate a thumbnail image of an original image comprising blocks encoded by intra prediction, the blocks of the original image are decoded to obtain an original image, and the original image then needs to be used. Therefore, the computations and time required for generating the reduced image are increased.
In particular, H.264 supports an Adaptive Frame/Field (AFF) encoding technique, and accordingly, there is a need for a method for generating a reduced image of an original image without decoding blocks of the original image encoded using the AFF encoding technique.